Migrate remaining mailers to format_mail_html / format_mail_text (#23387)

The view-helper migration introduced by the parent PR now covers the
remaining mailer surfaces: UserMailer (`message_posted`, `news_added`,
`news_comment_added`), ProjectMailer (`project_created`),
ProjectArtifactsMailer (`creation_wizard_submitted`), MemberMailer
(`added_project`, `updated_project`, `updated_global`), AnnouncementMailer
(`announce`), DocumentsMailer (`document_added`), and the shared mailer
layout (`localized_emails_header`, `localized_emails_footer`).

Sites drop the `static_html: true` / `only_path: false` / `plain_text: true`
boilerplate; `render_mode:` pinning lives in the helper.

The layout previously called `OpenProject::TextFormatting::Renderer.format_text`
directly, bypassing the helper layer. The empty visibility cache (no
current_user-scoped preload at layout time) is handled by the existing
fallback in `LinkHandlers::WorkPackages#text_only?` — covered by a new
sanity spec in `user_mailer_spec.rb` that exercises the header path with
a WP reference and asserts plain-text formatted_id rendering.

Per-bucket regression coverage added: absolute-URL and formatted_id
assertions across both classic and semantic identifier modes, mirroring
the WorkPackageMailer spec pattern.

Author: akabiru

app/views/announcement_mailer/announce.html.erb

@@ -13,20 +13,20 @@
           <% if body_subheader %>
             <tr>
               <td style="<%= placeholder_text_styles("font-weight": "bold") %>">
-                <%= format_text body_subheader %>
+                <%= format_mail_html body_subheader %>
               </td>
             </tr>
           <% end %>
           <% if body_header %>
             <tr>
               <td style="<%= placeholder_text_styles(color: "#333333", "line-height": "36px", "font-size": "18px", "font-weight": "bold") %>">
-                <%= format_text body_header %>
+                <%= format_mail_html body_header %>
               </td>
             </tr>
           <% end %>
           <tr>
             <td style="<%= placeholder_text_styles %>">
-              <%= format_text body %>
+              <%= format_mail_html body %>
             </td>
           </tr>
         </table>

app/views/layouts/mailer.html.erb

@@ -102,7 +102,7 @@ See COPYRIGHT and LICENSE files for more details.
       <table class="header">
         <tr>
           <td>
-            <%= OpenProject::TextFormatting::Renderer.format_text(Setting.localized_emails_header) %>
+            <%= format_mail_html(Setting.localized_emails_header) %>
           </td>
         </tr>
       </table>
@@ -118,7 +118,7 @@ See COPYRIGHT and LICENSE files for more details.
       <table class="footer">
         <tr>
           <td>
-            <%= OpenProject::TextFormatting::Renderer.format_text(Setting.localized_emails_footer) %>
+            <%= format_mail_html(Setting.localized_emails_footer) %>
           </td>
         </tr>
       </table>

app/views/member_mailer/added_project.html.erb

@@ -6,7 +6,7 @@
   )
 %>
 
-<%= format_text(@message) %>
+<%= format_mail_html(@message) %>
 
 <%= I18n.t(:"mail_member_added_project.body.roles") %>
 <ul>

app/views/member_mailer/updated_global.html.erb

@@ -5,7 +5,7 @@
   )
 %>
 
-<%= format_text(@message) %>
+<%= format_mail_html(@message) %>
 
 <%= I18n.t(:"mail_member_updated_global.body.roles") %>
 <ul>

app/views/member_mailer/updated_project.html.erb

@@ -6,7 +6,7 @@
   )
 %>
 
-<%= format_text(@message) %>
+<%= format_mail_html(@message) %>
 
 <%= I18n.t(:"mail_member_updated_project.body.roles") %>
 <ul>

app/views/project_artifacts_mailer/creation_wizard_submitted.html.erb

@@ -29,7 +29,7 @@ See COPYRIGHT and LICENSE files for more details.
 
 <h1><%= link_to @project.name, project_url(@project) %></h1>
 
-<%= format_text(@notification_text, project: @project) %>
+<%= format_mail_html(@notification_text, project: @project) %>
 
 <% if @work_package&.visible? %>
   <p>

app/views/project_mailer/project_created.html.erb

@@ -29,7 +29,7 @@ See COPYRIGHT and LICENSE files for more details.
 
 <h1><%= link_to @project.name, project_url(@project) %></h1>
 
-<%= format_text(@notification_text, project: @project) %>
+<%= format_mail_html(@notification_text, project: @project) %>
 
 <% if @project.project_creation_wizard_enabled? %>
   <p>

app/views/user_mailer/message_posted.html.erb

@@ -32,4 +32,4 @@ See COPYRIGHT and LICENSE files for more details.
 </h1>
 <em><%= @message.author %></em>
 
-<%= format_text @message.content, object: @message, only_path: false %>
+<%= format_mail_html @message.content, object: @message %>

app/views/user_mailer/news_added.html.erb

@@ -30,4 +30,4 @@ See COPYRIGHT and LICENSE files for more details.
 <h1><%= link_to @news.title, project_news_url(@news.project, @news) %></h1>
 <em><%= @news.author&.name %></em>
 
-<%= format_text @news.description, only_path: false %>
+<%= format_mail_html @news.description %>

app/views/user_mailer/news_comment_added.html.erb

@@ -31,4 +31,4 @@ See COPYRIGHT and LICENSE files for more details.
 
 <p><%= t(:text_user_wrote, value: @comment.author) %></p>
 
-<%= format_text @comment.text, only_path: false %>
+<%= format_mail_html @comment.text %>